libcurl编译使用，实现ftp功能

Libcurl实现ftp的下载，上传功能。版本为curl-7.63.0

1、编译vs2015

参考资料：https://blog.csdn.net/yaojingkao/article/details/53044361

2、libcurl传输进度参考：

https://blog.csdn.net/u012234115/article/details/83869486

3、libcurl使用方法参考：

https://www.cnblogs.com/mengfanrong/p/4581068.html

4、在搜索资料的时候，应该注意libcurl版本的问题，不同的版本，用法可能不同。

5、断点续传：

https://www.cnblogs.com/chang290/archive/2012/08/12/2634858.html

官网下载：

解压到本地，使用vs2015打开解决方案：

选择libcurl，DLL Release，32位，进行编译

编译完成后，生成的库文件libcurl.dll  和 libcurl.lib 在下面的目录中

2、使用：vs2015新建测试工程：

需要libcurl的头文件跟动态库。

libcurl头文件路径：

将libcurl头文件跟库文件，放到ftptest.sln解决方案下面

在ftptest.sln同级目录下，新建include和lib目录

将libcurl的头文件拷贝到include目录下

将libcurl的库拷贝到lib目录下目录下

将libcurl头文件加入到工程配置中：

将libcurl库加入到工程配置中：

在工程中连接libcurl库：

对libcurl进行c++封装，测试，c++使用Qt

头文件：

#ifndef FTPLIBCURL_H

#define FTPLIBCURL_H

#include "curl/curl.h"

#include "curl/easy.h"

#include <QObject>

class FtpLibCurl;

struct CustomProgress

{

curl_off_t lastruntime; /* type depends on version, see above */

CURL *curl;

FtpLibCurl* p;

};

class FtpLibCurl : public QObject

{

Q_OBJECT

public:

FtpLibCurl(QObject *parent);

~FtpLibCurl();

public:

void getProg(qulonglong);

void setFile(const QString&);

public slots:

void process();

void downFile();

signals:

void finished();

void error(QString err);

void ftp_prog(QString);

public:

struct CustomProgress prog;

private:

qulonglong m_fileSize;

QString m_s_percentage;

QString m_fileName;

};

#endif // FTPLIBCURL_H

Cpp文件：

#include "FtpLibCurl.h"

//#define F_LOCAL_FILE     "F:/1.jpg"

//#define F_REMOTE_URL     "ftp://192.168.16.166:21//home/msj/1.jpg"

size_t f_read_callback(void *ptr, size_t size, size_t nmemb, void *stream) //回调函数

{

curl_off_t nread;

size_t retcode = fread(ptr, size, nmemb, (FILE*)(stream));

nread = (curl_off_t)retcode;

return retcode;

}

// work for both download and upload

int progressCallback(void *p,

curl_off_t dltotal,

curl_off_t dlnow,

curl_off_t ultotal,

curl_off_t ulnow)

{

struct CustomProgress *progress = (struct CustomProgress *)p;

CURL *curl = progress->curl;

curl_off_t curtime = 0;

curl_easy_getinfo(curl, CURLINFO_TOTAL_TIME_T, &curtime);

/* under certain circumstances it may be desirable for certain functionality

to only run every N seconds, in order to do this the transaction time can

be used */

if ((curtime - progress->lastruntime) >= 3000000)

{

progress->lastruntime = curtime;

//printf("TOTAL TIME: %f \n", curtime);

}

// do something to display the progress

//printf("UP: %ld bytes of %ld bytes, DOWN: %ld bytes of %ld bytes \n", ulnow, ultotal, dlnow, dltotal);

if (ultotal)

{

//printf("UP progress: %0.2f\n", float(ulnow / ultotal));

progress->p->getProg(ulnow);

}

if (dltotal)

{

//("DOWN progress: %0.2f\n", float(dlnow / dltotal));

}

return 0;

}

FtpLibCurl::FtpLibCurl(QObject *parent)

: QObject(parent)

{

prog = {0};

m_s_percentage = QString("0%");

m_fileName.clear();

}

FtpLibCurl::~FtpLibCurl()

{

}

void FtpLibCurl::process()

{

CURL *pCurlhandle;

CURLcode res;

FILE *hd_src;

struct stat file_info;

curl_off_t fsize;

QByteArray ba = m_fileName.toLocal8Bit();

const char *c_str = ba.constData();

/*1. 获取待上传文件的大小 */

if (stat(c_str, &file_info)) {

printf("Couldnt open '%s': %s\n", c_str, strerror(errno));

emit error(QString("local file not exist"));

return;

}

fsize = (curl_off_t)file_info.st_size;

m_fileSize = fsize;

/*2. 获取待上传文件的描写叙述符 */

hd_src = fopen(c_str, "rb");

/*3. 初始化全部可能的调用*/

curl_global_init(CURL_GLOBAL_ALL);

/*4. 创建一个curlhandle*/

pCurlhandle = curl_easy_init();

if (pCurlhandle)

{

curl_easy_setopt(pCurlhandle, CURLOPT_USERPWD, "msj:msj");

/*5.设置一个回调函数 */

curl_easy_setopt(pCurlhandle, CURLOPT_READFUNCTION, f_read_callback);

/*6.使能上传标志位 */

curl_easy_setopt(pCurlhandle, CURLOPT_UPLOAD, 1L);

/*7.指定ftpserver的url */

QStringList path_list = m_fileName.split('/');

QString tmp_url = "ftp://192.168.16.166:21//home/xx/" + path_list.last();

QByteArray url_ba = tmp_url.toLocal8Bit();

const char *url_str = url_ba.constData();

curl_easy_setopt(pCurlhandle, CURLOPT_URL, url_str);

/*8.指定须要上传的文件 */

curl_easy_setopt(pCurlhandle, CURLOPT_READDATA, hd_src);

/*9.设置待上传文件的大小，这个大小是上面获取到的注意：当參数

为CURLOPT_INFILESIZE_LARGE的时候。size类型应该是curl_off_t的，

当參数为CURLOPT_INFILESIZE的时候size应该是long类型的*/

curl_easy_setopt(pCurlhandle, CURLOPT_INFILESIZE_LARGE,

(curl_off_t)fsize);

// set upload progress

curl_easy_setopt(pCurlhandle, CURLOPT_XFERINFOFUNCTION, progressCallback);

curl_easy_setopt(pCurlhandle, CURLOPT_XFERINFODATA, &prog);

prog.p = this;

curl_easy_setopt(pCurlhandle, CURLOPT_NOPROGRESS, 0);

/*10. 開始运行我们上述设定的方法*/

res = curl_easy_perform(pCurlhandle);

/*11. 检查是否运行成功 */

if (res != CURLE_OK)

{

fprintf(stderr, "curl_easy_perform() failed: %s\n",

curl_easy_strerror(res));

emit error(QString(curl_easy_strerror(res)));

}

/*12. 关闭pCurlhandle*/

curl_easy_cleanup(pCurlhandle);

}

fclose(hd_src); /* close the local file */

/*13. 清除全部可能的调用*/

curl_global_cleanup();

emit finished();

}

void FtpLibCurl::getProg(qulonglong v)

{

int int_percentage = (v / m_fileSize)*100;

QString tmp_percentage = QString::number(int_percentage) + "%";

if (m_s_percentage!= tmp_percentage)

{

m_s_percentage = tmp_percentage;

emit ftp_prog(tmp_percentage);

}

}

void FtpLibCurl::downFile()

{

}

void FtpLibCurl::setFile(const QString& s)

{

m_fileName = s;

}

测试代码：

QThread *thread = new QThread();

FtpLibCurl *worker = new FtpLibCurl(nullptr);

worker->setFile(QString("F:/1.jpg"));

worker->moveToThread(thread);

// 错误处理

connect(worker, SIGNAL(error(QString)), this, SLOT(errorString(QString)));

// 处理数据

connect(thread, SIGNAL(started()), worker, SLOT(process()));

// 退出、删除

connect(worker, SIGNAL(error(QString)), this, SLOT(ftp_error(QString)));

connect(worker, SIGNAL(finished()), thread, SLOT(quit()));

connect(worker, SIGNAL(finished()), worker, SLOT(deleteLater()));

connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));

// 启动线程

thread->start();